drm/xe/pf: Add helpers for migration data packet allocation / free

Now that it's possible to free the packets - connect the restore
handling logic with the ring.
The helpers will also be used in upcoming changes that will start
producing migration data packets.

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patch.msgid.link/20251112132220.516975-7-michal.winiarski@intel.com
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>

drivers/gpu/drm/xe/Makefile

@@ -174,6 +174,7 @@ xe-$(CONFIG_PCI_IOV) += \
 	xe_lmtt_2l.o \
 	xe_lmtt_ml.o \
 	xe_pci_sriov.o \
+	xe_sriov_packet.o \
 	xe_sriov_pf.o \
 	xe_sriov_pf_control.o \
 	xe_sriov_pf_debugfs.o \

drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c

@@ -18,6 +18,7 @@
 #include "xe_gt_sriov_printk.h"
 #include "xe_guc_ct.h"
 #include "xe_sriov.h"
+#include "xe_sriov_packet.h"
 #include "xe_sriov_packet_types.h"
 #include "xe_sriov_pf_control.h"
 #include "xe_sriov_pf_migration.h"
@@ -853,6 +854,8 @@ int xe_gt_sriov_pf_control_resume_vf(struct xe_gt *gt, unsigned int vfid)
 static void pf_exit_vf_save_wip(struct xe_gt *gt, unsigned int vfid)
 {
 	if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WIP)) {
+		xe_gt_sriov_pf_migration_ring_free(gt, vfid);
+
 		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_PROCESS_DATA);
 		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WAIT_DATA);
 		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_DATA_DONE);
@@ -1075,6 +1078,8 @@ int xe_gt_sriov_pf_control_finish_save_vf(struct xe_gt *gt, unsigned int vfid)
 static void pf_exit_vf_restore_wip(struct xe_gt *gt, unsigned int vfid)
 {
 	if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WIP)) {
+		xe_gt_sriov_pf_migration_ring_free(gt, vfid);
+
 		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_PROCESS_DATA);
 		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_WAIT_DATA);
 		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_DATA_DONE);
@@ -1109,6 +1114,8 @@ static int pf_handle_vf_restore_data(struct xe_gt *gt, unsigned int vfid)
 
 	xe_gt_sriov_notice(gt, "Skipping VF%u unknown data type: %d\n", vfid, data->hdr.type);
 
+	xe_sriov_packet_free(data);
+
 	return 0;
 }
 
@@ -1202,8 +1209,10 @@ int xe_gt_sriov_pf_control_restore_data_done(struct xe_gt *gt, unsigned int vfid
  */
 int xe_gt_sriov_pf_control_process_restore_data(struct xe_gt *gt, unsigned int vfid)
 {
-	if (!pf_expect_vf_not_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_FAILED))
+	if (!pf_expect_vf_not_state(gt, vfid, XE_GT_SRIOV_STATE_RESTORE_FAILED)) {
+		xe_gt_sriov_pf_migration_ring_free(gt, vfid);
 		return -EIO;
+	}
 
 	pf_exit_vf_restore_wait_data(gt, vfid);
 

drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.c

@@ -14,6 +14,7 @@
 #include "xe_guc.h"
 #include "xe_guc_ct.h"
 #include "xe_sriov.h"
+#include "xe_sriov_packet.h"
 #include "xe_sriov_packet_types.h"
 #include "xe_sriov_pf_migration.h"
 
@@ -419,6 +420,25 @@ bool xe_gt_sriov_pf_migration_ring_full(struct xe_gt *gt, unsigned int vfid)
 	return ptr_ring_full(&pf_pick_gt_migration(gt, vfid)->ring);
 }
 
+/**
+ * xe_gt_sriov_pf_migration_ring_free() - Consume and free all data in migration ring
+ * @gt: the &xe_gt
+ * @vfid: the VF identifier
+ */
+void xe_gt_sriov_pf_migration_ring_free(struct xe_gt *gt, unsigned int vfid)
+{
+	struct xe_gt_sriov_migration_data *migration = pf_pick_gt_migration(gt, vfid);
+	struct xe_sriov_packet *data;
+
+	if (ptr_ring_empty(&migration->ring))
+		return;
+
+	xe_gt_sriov_notice(gt, "VF%u unprocessed migration data left in the ring!\n", vfid);
+
+	while ((data = ptr_ring_consume(&migration->ring)))
+		xe_sriov_packet_free(data);
+}
+
 /**
  * xe_gt_sriov_pf_migration_save_produce() - Add VF save data packet to migration ring.
  * @gt: the &xe_gt
@@ -545,8 +565,10 @@ xe_gt_sriov_pf_migration_save_consume(struct xe_gt *gt, unsigned int vfid)
 	data = ptr_ring_consume(&migration->ring);
 	if (data) {
 		ret = xe_gt_sriov_pf_control_process_save_data(gt, vfid);
-		if (ret)
+		if (ret) {
+			xe_sriov_packet_free(data);
 			return ERR_PTR(ret);
+		}
 
 		return data;
 	}
@@ -560,11 +582,18 @@ xe_gt_sriov_pf_migration_save_consume(struct xe_gt *gt, unsigned int vfid)
 	return ERR_PTR(-EAGAIN);
 }
 
+static void destroy_pf_packet(void *ptr)
+{
+	struct xe_sriov_packet *data = ptr;
+
+	xe_sriov_packet_free(data);
+}
+
 static void action_ring_cleanup(void *arg)
 {
 	struct ptr_ring *r = arg;
 
-	ptr_ring_cleanup(r, NULL);
+	ptr_ring_cleanup(r, destroy_pf_packet);
 }
 
 /**

drivers/gpu/drm/xe/xe_gt_sriov_pf_migration.h

@@ -17,6 +17,7 @@ int xe_gt_sriov_pf_migration_restore_guc_state(struct xe_gt *gt, unsigned int vf
 
 bool xe_gt_sriov_pf_migration_ring_empty(struct xe_gt *gt, unsigned int vfid);
 bool xe_gt_sriov_pf_migration_ring_full(struct xe_gt *gt, unsigned int vfid);
+void xe_gt_sriov_pf_migration_ring_free(struct xe_gt *gt, unsigned int vfid);
 
 int xe_gt_sriov_pf_migration_save_produce(struct xe_gt *gt, unsigned int vfid,
 					  struct xe_sriov_packet *data);

drivers/gpu/drm/xe/xe_sriov_packet.c

@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#include "xe_bo.h"
+#include "xe_device.h"
+#include "xe_printk.h"
+#include "xe_sriov_packet.h"
+#include "xe_sriov_packet_types.h"
+
+static bool pkt_needs_bo(struct xe_sriov_packet *data)
+{
+	return data->hdr.type == XE_SRIOV_PACKET_TYPE_VRAM;
+}
+
+/**
+ * xe_sriov_packet_alloc() - Allocate migration data packet
+ * @xe: the &xe_device
+ *
+ * Only allocates the "outer" structure, without initializing the migration
+ * data backing storage.
+ *
+ * Return: Pointer to &xe_sriov_packet on success,
+ *         NULL in case of error.
+ */
+struct xe_sriov_packet *xe_sriov_packet_alloc(struct xe_device *xe)
+{
+	struct xe_sriov_packet *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return NULL;
+
+	data->xe = xe;
+	data->hdr_remaining = sizeof(data->hdr);
+
+	return data;
+}
+
+/**
+ * xe_sriov_packet_free() - Free migration data packet.
+ * @data: the &xe_sriov_packet
+ */
+void xe_sriov_packet_free(struct xe_sriov_packet *data)
+{
+	if (IS_ERR_OR_NULL(data))
+		return;
+
+	if (pkt_needs_bo(data))
+		xe_bo_unpin_map_no_vm(data->bo);
+	else
+		kvfree(data->buff);
+
+	kfree(data);
+}
+
+static int pkt_init(struct xe_sriov_packet *data)
+{
+	struct xe_gt *gt = xe_device_get_gt(data->xe, data->hdr.gt_id);
+
+	if (!gt)
+		return -EINVAL;
+
+	if (data->hdr.size == 0)
+		return 0;
+
+	if (pkt_needs_bo(data)) {
+		struct xe_bo *bo;
+
+		bo = xe_bo_create_pin_map_novm(data->xe, gt->tile, PAGE_ALIGN(data->hdr.size),
+					       ttm_bo_type_kernel,
+					       XE_BO_FLAG_SYSTEM | XE_BO_FLAG_PINNED, false);
+		if (IS_ERR(bo))
+			return PTR_ERR(bo);
+
+		data->bo = bo;
+		data->vaddr = bo->vmap.vaddr;
+	} else {
+		void *buff = kvzalloc(data->hdr.size, GFP_KERNEL);
+
+		if (!buff)
+			return -ENOMEM;
+
+		data->buff = buff;
+		data->vaddr = buff;
+	}
+
+	return 0;
+}
+
+#define XE_SRIOV_PACKET_SUPPORTED_VERSION 1
+
+/**
+ * xe_sriov_packet_init() - Initialize migration packet header and backing storage.
+ * @data: the &xe_sriov_packet
+ * @tile_id: tile identifier
+ * @gt_id: GT identifier
+ * @type: &xe_sriov_packet_type
+ * @offset: offset of data packet payload (within wider resource)
+ * @size: size of data packet payload
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_sriov_packet_init(struct xe_sriov_packet *data, u8 tile_id, u8 gt_id,
+			 enum xe_sriov_packet_type type, loff_t offset, size_t size)
+{
+	data->hdr.version = XE_SRIOV_PACKET_SUPPORTED_VERSION;
+	data->hdr.type = type;
+	data->hdr.tile_id = tile_id;
+	data->hdr.gt_id = gt_id;
+	data->hdr.offset = offset;
+	data->hdr.size = size;
+	data->remaining = size;
+
+	return pkt_init(data);
+}
+
+/**
+ * xe_sriov_packet_init_from_hdr() - Initialize migration packet backing storage based on header.
+ * @data: the &xe_sriov_packet
+ *
+ * Header data is expected to be filled prior to calling this function.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_sriov_packet_init_from_hdr(struct xe_sriov_packet *data)
+{
+	xe_assert(data->xe, !data->hdr_remaining);
+
+	if (data->hdr.version != XE_SRIOV_PACKET_SUPPORTED_VERSION)
+		return -EINVAL;
+
+	data->remaining = data->hdr.size;
+
+	return pkt_init(data);
+}

drivers/gpu/drm/xe/xe_sriov_packet.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#ifndef _XE_SRIOV_PACKET_H_
+#define _XE_SRIOV_PACKET_H_
+
+#include <linux/types.h>
+
+struct xe_device;
+struct xe_sriov_packet;
+enum xe_sriov_packet_type;
+
+struct xe_sriov_packet *xe_sriov_packet_alloc(struct xe_device *xe);
+void xe_sriov_packet_free(struct xe_sriov_packet *data);
+
+int xe_sriov_packet_init(struct xe_sriov_packet *data, u8 tile_id, u8 gt_id,
+			 enum xe_sriov_packet_type, loff_t offset, size_t size);
+int xe_sriov_packet_init_from_hdr(struct xe_sriov_packet *data);
+
+#endif

drivers/gpu/drm/xe/xe_sriov_packet_types.h

@@ -8,6 +8,25 @@
 
 #include <linux/types.h>
 
+/**
+ * enum xe_sriov_packet_type - Xe SR-IOV VF migration data packet type
+ * @XE_SRIOV_PACKET_TYPE_DESCRIPTOR: Descriptor with VF device metadata
+ * @XE_SRIOV_PACKET_TYPE_TRAILER: Trailer indicating end-of-stream
+ * @XE_SRIOV_PACKET_TYPE_GGTT: Global GTT migration data
+ * @XE_SRIOV_PACKET_TYPE_MMIO: MMIO registers migration data
+ * @XE_SRIOV_PACKET_TYPE_GUC: GuC firmware migration data
+ * @XE_SRIOV_PACKET_TYPE_VRAM: VRAM migration data
+ */
+enum xe_sriov_packet_type {
+	/* Skipping 0 to catch uninitialized data */
+	XE_SRIOV_PACKET_TYPE_DESCRIPTOR = 1,
+	XE_SRIOV_PACKET_TYPE_TRAILER,
+	XE_SRIOV_PACKET_TYPE_GGTT,
+	XE_SRIOV_PACKET_TYPE_MMIO,
+	XE_SRIOV_PACKET_TYPE_GUC,
+	XE_SRIOV_PACKET_TYPE_VRAM,
+};
+
 /**
  * struct xe_sriov_packet_hdr - Xe SR-IOV VF migration data packet header
  */